136 
PALEONTOLOGY OF NEW YORK. 
that the more fragile portions of the ribbon are lost, leaving only the umbonal 
blades and the loop. 
The same details both of exterior and interior structure have been observed 
in the species Codlospira Camilla, Hall, of the Corniferous limestone of New York 
and Canada, and, with the exception of the brachial apparatus, in the Atrypa 
acutiplicata, Conrad, of the same fauna. It is clearly evident that the structure 
in the species of Coelospira here mentioned, is essentially the same as in 
Anoplotheca venusta and A. {Bifida) lepida. The only material difference, that can 
now be indicated between these forms, is one of greater geological than 
biological significance; the later, or middle Devonian forms (Anoplotheca) 
being more convex, more coarsely and sparsely plicated and more strongly 
striated concentrically. Upon this basis of distinction the name Ccelospira 
may be retained with a subgeneric value. 
There are a few species in the Clinton fauna which have the outward expres¬ 
sion of Ccelospira, and agree with it in the structure of the articulating appa¬ 
ratus. These species are Atrypa plicatula, Hall, A. planoconvexa, Hall, and 
A. hemisphcurica (Sowerby), Hall (= Leptocodia hemispherica, Davidson). The 
brachidium in these forms is not yet known, and their reference to Ccelospira 
is therefore provisional. 
Genus LEPTOCCELIA, Hall. 1859. 
PLATE LIII. 
1841. Atrypa, Conrad. Geol. Survey N. Y.; Rept. Palseont. Dept., p. 55. 
1846. Atrypa, Morris and Sharpe. Quart. Jour. Geol. Soc., vol. ii, p. 276, pi. x, fig. 3. 
1856. Orthis, Sharpe and Salter. Trans. Geol. Society London, second ser., vol. vii, p. 203. 
1857. Leptoccelia, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. History, p. 108. 
1859. Leptoccelia, Hall. Palseont. of N. Y., vol. iii, pp. 449-452, pi. ciii b, figs. 1 a-g; pi. cvi, figs. 1 a-f. 
1861. Orthis, Salter. Quart. Jour. Geol. Society, vol. xvii, p. 68, pi. iv, fig. 14. 
1868. Leptoccelia, Meek and Worthen. Geol. Surv. Illinois, vol. iii, p. 397, pi. viii, figs. 3 a-c. 
1892. Leptoccelia, Ulrich. Palseozoische Verstein. aus Bolivien: Neues Jahrb. fiir Mineral., etc., 
Beilagebnd. viii, p. 60, pi. iv, figs. 9 a, h, 10-13. 
The typical species of this group is L. flabellites, Conrad, of the Oriskany 
sandstone; a shell which differs, as far as its structure is known, from Ctzlospira 
concava, only in its greater size and coarser, simple plication of the surface. In 
general contour, structure of hinge, cardinal process, muscular scars and inter- 
